The prior art is aware of utility vehicles, such as tractors and trucks which support, power and transport attachments or implements, such as those disclosed in the patents cited herein. These vehicles can traverse the ground while the attachment is performing its work, such as in the present instance of the application of turf fertilizer, top dressing, pesticides, grass mowing, or the like. These vehicles are engine powered and hydraulically driven, and they also include electric controls, and one arrangement of such is disclosed in U.S. Pat. No. 5,074,373 which, to the extent of its disclosure, it may be considered as being incorporated herein.
The present invention is concerned with an engine-driven vehicle which includes a hydraulic system for mobilizing the vehicle and which also includes hydraulics for powering attachments supported by the vehicle. Further, electronic controls are included, and they influence the engine and the power-take-off control for the attachment such that the attachment can be operated at a constant speed while the vehicle traverses the ground at a constant speed, all so the work performance of the attachment is desirably consistent relative to the speed of traversing the ground.
That is, for uniformity of the work performance of the attachment as the vehicle traverses the ground, the vehicle ground speed is at a constant rate so that the attachment properly performs its function at a desired operational speed, such as for in application of fertilizer, top dressing, spraying, mowing and the like.
Two other U.S. patents in the area of engine speed control and/or hydraulic systems are U.S. Pat. Nos. 5,417,193 and 5,649,606, both of which are incorporated herein by this reference thereto.
The invention utililizes electronics and hydraulics for precise control of mowing and the application of fertilizer, top dressing, pesticides, and any other product requiring precise application, including constant ground speed of the vehicle. This allows the vehicle to be set up for a particular job, and, with a computer in the vehicle, it gives the operator full records of application rates and vehicle operational settings. By full closed loop control the chance of misapplication is minimized, and also wasted material is minimized. Operator abuse is also minimized, and the acceleration rates can be programmed for forward and reverse movement, and the maximum speeds can be programmed for ground speed and engine speed .